Any of the modern trials bikes are great.
I picked up a clean 01 Sherco last year for $2500 US (plus $300 shipping).
In general, Trials bikes are good used buys. Except for the real advanced/expert riders, the engines don't get reved out much. It's all pretty low speed riding. They get a bit beat up from falls, but damage is almost always aesthetic. The bikes are so well made that it is rare to actually damage anything but the plastic (I did bend a shift lever once).
Good luck on your search. Trials is a blast and a good way to improve your skills. Plus, you can practice balancing in your garage on those cold Canadian nights :)